This proposal compares daily agonist maintenance on either Buprenorphine 12 mg SL or Methadone 65 mg PO when combined with a manual guided treatment emphasizing either a community reinforcement approach (CRA) alone or CRA plus contingency management (CM) for the treatment of concurrent opioid and cocaine dependence. While there is a compelling need to develop buprenorphine as an alternative to methadone for agonist maintenance treatment of opioid dependence, neither agent is particularly effective for treating concurrent cocaine dependence. CRA combined with CM has shown great promise as treatment for cocaine dependence without concurrent opioid dependence, and we are interested in replicating and extending the generalizability of this approach to an inner city setting with patients dependent on both opioids and cocaine treated in an agonist maintenance program. Our primary aims in this 26 week clinical trial and six month follow-up are 1) to evaluate whether CRA with CM is more effective overall than CRA without CM in reducing illicit opioid and cocaine use; and 2) to compare the efficacy of maintenance on buprenorphine to methadone, when maintenance is combined with CRA with or without CM. Subjects with concurrent opioid and cocaine dependence (N= 168) will be randomly assigned to treatment condition, using an urn randomization technique to assure balanced cells with regard to important baseline characteristics. Medications will be administered in a double blind, double dummy design. Behavioral treatments will be administered by experienced clinicians who wiIl be systematically trained and supervised throughout the study. Primary outcome measures include reduction in opioid and cocaine use, as assessed by three times per week urine toxicology testing during the 26-week trial. Additional outcome measures include retention in treatment and self-report measures of reductions in drug use and improvements in psychosocial functioning, based on weekly self-report and repeated monthly ASI measures. Data analysis will be based on an intention to treat sample. Follow-up assessments at 3 and 6 months after completion of the treatment protocol will allow evaluation of the durability of treatment effects.